<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii">
<META NAME="Generator" CONTENT="MS Exchange Server version 6.0.6249.1">
<TITLE>Pt bulk phonon calculated by PWSCF 1.2.0</TITLE>
</HEAD>
<BODY>
<!-- Converted from text/rtf format -->
<P><FONT SIZE=2 FACE="Arial">Hello, dear PWSCF users</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">Recently I calculated the bulk phonons of Pt along Gamma-K direction.</FONT>
<BR><FONT SIZE=2 FACE="Arial">I attached the results in pdf format, where B,C and D are the ones calculated using PWSCF 1.2.0 version.</FONT>
<BR><FONT SIZE=2 FACE="Arial">The open circles are done by a mixed-basis code. The comparison shows that the frequencies obtained by</FONT>
<BR><FONT SIZE=2 FACE="Arial">PWSCF are showing some lowering of frequencies but oveall it's failing to reproduce the experimentally-observed anomaly in bulk Pt dispersion </FONT></P>
<P><FONT SIZE=2 FACE="Arial">along Gamma-K line while a mixed basis program is doing good job.</FONT>
<BR><FONT SIZE=2 FACE="Arial">I used ecut of 35 ryd for H/Pt US potentials and 72 special k-points. I increased the ecut to 40 ryd but just very slight changes in frequecies.</FONT></P>
<P><FONT SIZE=2 FACE="Arial">I also tried higher cut-off for charge density up to 10 times of ecut but just very small changes in frequencies.</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">What else can I try to get better frequencies for bulk Pt? Could any of you give me some informations ? You will be very appreciated. </FONT></P>
<P><FONT SIZE=2 FACE="Arial">Sampyo</FONT>
</P>
<P><FONT FACE="Arial" SIZE=2 COLOR="#000000"> <<ptbulk2.pdf>> </FONT>
</P>
</BODY>
</HTML>